1. Field of the Invention
The present invention relates generally to readily assembled molded shelving with height adjustable shelves.
2. Description of the Prior Art
Several types of adjustable shelving systems have been employed in the prior art. One type of system has corner posts provided with recesses around their exterior with adjustable, multi-part shelf supports fastened around each support post within a recess. An embodiment of such a support has two pieces which form a frusto-conical shaped exterior and a projecting rib member on the interior wall. The shelf supports are fastened to the corner posts with the rib engaging a corner post recess to retain the shelf support in place on the corner post. The shelf support frusto-conical exterior is mated with a frusto-conical recess in a shelf member such that the shelf member is wedged over the shelf support in fixed relationship with the corner post. Representative of this type of shelving systems are U.S. Pat. No. 3,424,111 to Maslow, U.S. Pat. No. 4,318,352 to Friedman, et al., U.S. Pat. No. 3,757,705 to Maslow, U.S. Pat. No. 3,523,508 to Maslow, U.S. Pat. No. 3,874,511 to Maslow and U.S. Pat. No. 3,927,769 to Maslow, et al. One disadvantage of the shelving systems discussed above is the number of parts. As a result, a significant amount of time is spent in disassembling and reassembling when the height of the shelf is adjusted.
In addition to the above shelf support systems, several prior art patents describe the use of spaced elongated extrusions or ribs on one surface of a shelf member which are intended to reduce or eliminate bowing of the shelf member. One such system disclosing unitary spaced ribs on one surface of the shelf member is shown in U.S. Pat. No. 3,323,656 to Weiss et al. A similar pallet assembly is disclosed in U.S. Pat. No. 3,719,157 to Arcocha et al. However, in both cases, little reinforcement is provided to the shelf member transverse to the longitudinal axis of the ribs. Other approaches form grid structures of longitudinal and transverse ribs on one surface of a shelf or pallet. Representative of these types of pallets or shelves are U.S. Pat. No. 3,680,495 to Pike, U.S. Pat. No. 3,228,358 to Sepe et al., and U.S. Pat. No. 3,917,108 to Thurmen.